ACCURATE LITERAL TRANSLATION OF PCT INTERNATIONAL APPLICATION PCT/DE 01/02425, AS FILED Jun. 28, 2001 (WO 02 00500 A1)
The invention relates to a decompression unit for equalizing an explosive air pressure between pressurized areas of an aircraft with different air pressure conditions. The different areas are separated from one another by a wall structure.
Since the seventies of the 20th century pressurized cabins of commercial aircraft are equipped with a system for the rapid equalization of the air pressure in the individual aircraft areas so that a sudden pressure drop in the affected area cannot lead to a failure of flight critical structures or systems. A large capacity commercial aircraft, a so-called wide body aircraft, has, as is known, a large volume in the passenger cabin area above the floor as well as in the freight area below the floor, whereby the venting cross-sectional area for the decompression air flow between these aircraft areas will be several times larger compared to the venting grid cross-section required for the normal venting.
System configurations are known wherein respective air slot pressure equalization openings or pressure equalization flaps are used. These systems are, as a rule, installed in the floor covering or in the floor area of the respective aircraft areas in order to provide additional air flow cross-section. A wide body commercial aircraft comprises more than one hundred of these so-called decompression units, one of which unit is installed for each aircraft window area. Such air slot pressure equalization openings are easily installed, whereby, however, the carry-on baggage of an aircraft passenger or other onboard kitchen articles can easily block these pressure equalization openings. Thus, these openings are considered to be undesired lay-out elements.
In actual lay-outs for wide body aircraft actuating flaps are used for an enforced ventilation of the airstream entering behind the pressure equalization flap as a so-called air return flow duct of the normal cabin venting. The individual flap will react in response to a given pressure difference present between the air return flow duct on the one hand and the low pressure level of the air below the cabin floor on the other hand. The flap will open in the direction outwardly, that is in the direction of the lower air pressure. For this purpose the locking bars which so far was locked to hold the flap within the structure surrounding the flap, is released or unlocked, whereby the pressure equalization flap is pressed outwardly, namely it is lifted off the surrounding structure so that now the excess cabin pressure can escape and a pressure equalization can take place.
In this type of decompression unit only components are used having a fine adjustment characteristic and a large surface area for achieving their purpose. These known constructions with pressure equalization flaps for decompression purposes are uniformly hard to classify, whereby due to their complicated construction additionally a respective effort and expense must be taken into account for the maintenance and undesired repairs.
In view of the above it is the object of the invention to improve a decompression application as defined above in such a way that a pressure equalization plate is equipped with a suitable mechanism which can also be retrofitted without a large effort and expense, which mechanism holds the pressure equalization plate during normal flight and also when an unintended loading or adjustment of the effective range due to diverse air passenger loads occur, in the structure surrounding the pressure equalization plate. Thereby it is required (compared to air passenger loads), that occurring low pressure loads do not cause the opening of the pressure equalization flap. However, the mechanism shall react to suddenly occurring small cabin air pressure changes. During the normal cruising flight including ascending and descending flight of an aircraft the mechanism shall be resistant to gradually changing air pressure conditions in the space of the respective aircraft area. More specifically, the mechanism shall not be sensitive to gradual small changes of the desired air pressure conditions. Additionally, the mechanism shall be independent of the size and shape of the pressure equalization flap. Moreover the mechanism shall work reliably while not using external energy sources. Furthermore, the improved decompression device as compared to actual system lay-outs shall provide a contribution to a weight reduction as compared to decompression function units operating solely for the purpose of decompression.